1=pod 2 3=head1 NAME 4 5EVP_RAND-CTR-DRBG - The CTR DRBG EVP_RAND implementation 6 7=head1 DESCRIPTION 8 9Support for the counter deterministic random bit generator through the 10B<EVP_RAND> API. 11 12=head2 Identity 13 14"CTR-DRBG" is the name for this implementation; it can be used with the 15EVP_RAND_fetch() function. 16 17=head2 Supported parameters 18 19The supported parameters are: 20 21=over 4 22 23=item "state" (B<OSSL_RAND_PARAM_STATE>) <integer> 24 25=item "strength" (B<OSSL_RAND_PARAM_STRENGTH>) <unsigned integer> 26 27=item "max_request" (B<OSSL_RAND_PARAM_MAX_REQUEST>) <unsigned integer> 28 29=item "reseed_requests" (B<OSSL_DRBG_PARAM_RESEED_REQUESTS>) <unsigned integer> 30 31=item "reseed_time_interval" (B<OSSL_DRBG_PARAM_RESEED_TIME_INTERVAL>) <integer> 32 33=item "min_entropylen" (B<OSSL_DRBG_PARAM_MIN_ENTROPYLEN>) <unsigned integer> 34 35=item "max_entropylen" (B<OSSL_DRBG_PARAM_MAX_ENTROPYLEN>) <unsigned integer> 36 37=item "min_noncelen" (B<OSSL_DRBG_PARAM_MIN_NONCELEN>) <unsigned integer> 38 39=item "max_noncelen" (B<OSSL_DRBG_PARAM_MAX_NONCELEN>) <unsigned integer> 40 41=item "max_perslen" (B<OSSL_DRBG_PARAM_MAX_PERSLEN>) <unsigned integer> 42 43=item "max_adinlen" (B<OSSL_DRBG_PARAM_MAX_ADINLEN>) <unsigned integer> 44 45=item "reseed_counter" (B<OSSL_DRBG_PARAM_RESEED_COUNTER>) <unsigned integer> 46 47=item "properties" (B<OSSL_DRBG_PARAM_PROPERTIES>) <UTF8 string> 48 49=item "cipher" (B<OSSL_DRBG_PARAM_CIPHER>) <UTF8 string> 50 51These parameters work as described in L<EVP_RAND(3)/PARAMETERS>. 52 53=item "use_derivation_function" (B<OSSL_DRBG_PARAM_USE_DF>) <integer> 54 55This Boolean indicates if a derivation function should be used or not. 56A nonzero value (the default) uses the derivation function. A zero value 57does not. 58 59=back 60 61=head1 NOTES 62 63A context for CTR DRBG can be obtained by calling: 64 65 EVP_RAND *rand = EVP_RAND_fetch(NULL, "CTR-DRBG", NULL); 66 EVP_RAND_CTX *rctx = EVP_RAND_CTX_new(rand); 67 68=head1 EXAMPLES 69 70 EVP_RAND *rand; 71 EVP_RAND_CTX *rctx; 72 unsigned char bytes[100]; 73 OSSL_PARAM params[2], *p = params; 74 unsigned int strength = 128; 75 76 rand = EVP_RAND_fetch(NULL, "CTR-DRBG", NULL); 77 rctx = EVP_RAND_CTX_new(rand, NULL); 78 EVP_RAND_free(rand); 79 80 *p++ = OSSL_PARAM_construct_utf8_string(OSSL_DRBG_PARAM_CIPHER, 81 SN_aes_256_ctr, 0); 82 *p = OSSL_PARAM_construct_end(); 83 EVP_RAND_instantiate(rctx, strength, 0, NULL, 0, params); 84 85 EVP_RAND_generate(rctx, bytes, sizeof(bytes), strength, 0, NULL, 0); 86 87 EVP_RAND_CTX_free(rctx); 88 89=head1 CONFORMING TO 90 91NIST SP 800-90A and SP 800-90B 92 93=head1 SEE ALSO 94 95L<EVP_RAND(3)>, 96L<EVP_RAND(3)/PARAMETERS> 97 98=head1 COPYRIGHT 99 100Copyright 2020-2021 The OpenSSL Project Authors. All Rights Reserved. 101 102Licensed under the Apache License 2.0 (the "License"). You may not use 103this file except in compliance with the License. You can obtain a copy 104in the file LICENSE in the source distribution or at 105L<https://www.openssl.org/source/license.html>. 106 107=cut 108